SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ceabae091eace03da020e9ca1dce80432da883258195adf575aee6fbf6dde58' 
  AND token = 'g7/BX45znnBZkKgGZLgf0igdqqakFnKlnbRC5KVgMqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}